How to size and cost a sandwich panel garage before choosing the door

Decide whether the garage simply shelters the car or will be a heated workshop. Workshop use requires appropriate walls and roof, tight joints and ventilation. Thicker panels alone cannot offset losses through a wide door and cold floor. Make this decision before ordering.

Check space for the car doors to swing and for a person to pass the shelving. The vehicle footprint alone is insufficient for choosing a comfortable internal width.

Take a garage measuring 5 × 7 m externally, with walls assumed to be 2.8 m high. The rectangular wall area is 24 × 2.8 = 67.2 m². A 3 × 2.3 m garage door and a 0.9 × 2 m side door give 8.7 m² of openings. That leaves 58.5 m² before any gables are added.

This gives the area to enclose. Lay out the actual panels above and beside the door, since an offcut may not be reusable. Calculate the roof separately from its sloping dimensions including the eaves. Floor area is insufficient. List lengths and piece counts for the order.

Suppose the cutting plan calls for 64 m² of wall panels at approximately €31.98/m² and 41 m² of roof panels at approximately €36.38/m², excluding VAT. Using unrounded unit rates, these lines cost €2,046.58 and €1,491.60, totalling €3,538.18 net. These hypothetical figures illustrate a budget, not a quotation or specification for a standard kit.

If flashings, seals and fasteners add €428.69, enclosure materials reach €3,966.87 net or €4,879.25 including an assumed 23% VAT. The frame, foundations, garage door, floor, services, delivery and labour are still outside this total. Include them when budgeting for the complete garage.

The frame sets panel support positions, while the panel choice constrains fastener layout. Check roof loads, wind, geometry and the actual panel configuration. Do not adopt the support spacing of a similar garage without calculation. Location or facing colour alone can change exposure conditions.

Plan plinth, corner and door surround details at the same time. Finish the bottom edge for its location and use. Keep driveway water from continually wetting it. Direct roof drainage away from the door and pedestrian route.

Provide room on site for the delivery vehicle and unloading equipment. Compare pack lengths with entrance width and turning space. Time delivery to suit the base and frame. Early delivery requires suitable storage. Transport film does not replace the covering specified in the instructions.

Before erection, check support dimensions and alignment. Verify the material batch, facing orientation and laying direction. Prepare flashings and openings from agreed drawings. Keep cutting temperatures low enough to protect the coating and remove swarf before it rusts on the surface.

Start handover by using the garage. Open the door to full height, try the side entrance and trace drainage at the eaves. Check plinth closures and flashings around openings. Look for swarf marks and leftover film. Agree a suitable leak test with the installer instead of flooding joints informally.

Keep panel identification, door documents and fixing details for maintenance and future shelving or services. Heavy equipment needs planned anchorage and cannot hang from an arbitrary point on a facing. Allow for future charging, heating or extraction equipment by planning penetrations and supports now.